Recently, along with the spread of mobile phones and the diversification of services therefor, a reduction of costs in maintaining mobile communication systems and adjusting such mobile communication systems for optimization is being requested. Examples of the items that need to be maintained and adjusted for optimization in such a mobile communication system include a transmission power level and an antenna tilt angle at a base station (which are also referred to as radio parameters) (see Patent Document 1).
The maintenance and adjustment of a communication system are generally performed based on an evaluation or examination which employs a radio network design simulator. In order to increase the accuracy of a simulation, information about reception statuses measured in service areas of a radio communication system and information about positions where measured values are obtained is input to the design simulator. For example, in a code division multiple access (CDMA) radio communication system, reception quality and strength of a common pilot channel are used as the reception status information.
Conventionally, the reception status information is measured by a dedicated measuring vehicle or a dedicated measuring team. Another conventional way is to have general mobile radio terminals owned by users measure the reception status information, to collect the measurement results. According to Patent Document 1, a mobile radio terminal monitors a user communication link status and detects, as a trigger, whether the link status satisfies a predetermined condition. When the trigger is detected, the mobile radio terminal acquires a radio signal reception status and the position of the mobile radio terminal. Next, the mobile radio terminal transmits measured information including the reception status and the position to a management server (information collection server), and the management server records the measured information received from the mobile radio terminal therein.
Patent Document 1: JP Patent Kokai Publication No. JP2004-166056 A
Non-Patent Document 1: “UE assistance for self-optimizing of network”, 3GPP TSG-RAN WG2 R2-072432, 25-29 Jun. 2007